Long-term air pollution exposure and lung function in 15 year-old adolescents living in an urban and rural area in Germany: The GINIplus and LISAplus cohorts

IntroductionThe impact of outdoor air pollution exposure on long-term lung development and potential periods of increased lung susceptibility remain unknown. This study assessed associations between early-life and current residential exposure to air pollution and lung function at 15-years of age in two German birth cohorts.MethodsFifteen year-old participants living in an urban and rural area in Germany underwent spirometry before and after bronchodilation (N = 2266). Annual average (long-term) exposure to nitrogen dioxide (NO₂), particles with aerodynamic diameters less than 2.5 μg/m³ (PM_2.5) mass and less than 10 μg/m³ (PM₁₀) mass, PM_2.5 absorbance and ozone were estimated to each participant's birth-, 10- and 15-year home address using land-use regression and kriging (ozone only) modelling. Associations between lung function variables and long-term pollutant concentrations were assessed using linear regression models adjusted for host and environmental covariates and recent short-term air pollution exposures.ResultsLong-term air pollution concentrations assessed to the birth-, 10- and 15-year home addresses were not associated with lung function variables, before and after bronchodilation, in the complete or study area specific populations. However, several lung function variables were negatively associated with long-term NO₂ concentrations among asthmatics. For example, NO₂ estimated to the 15-year home address was associated with the ratio of forced expiratory volume in one second to forced vital capacity (FEV₁/FVC) and the mean flow rate between 25% and 75% of FVC (−3.5%, 95% confidence interval [−6.0, −1.0] and −297.4 ml/s [−592.6, −2.1] per 5.9 μg/m³ increase in NO₂, respectively). Nearly all effect estimates for the associations between the short-term PM_2.5 mass, PM₁₀ mass and ozone concentrations and the lung function variables were negative in the complete population.ConclusionsEarly-life and current long-term air pollution exposures and lung function at the age of 15 years were not associated in the complete study population. Asthmatics may represent a vulnerable group.     

Exposure to fine particulate matter during pregnancy and risk of term low birth weight in Jinan,China, 2014–2016

Background

Existing studies exploring the association between low birth weight (LBW) and maternal fine particulate matter (aerodynamic diameter < 2.5 μm, PM_2.5) exposure have presented equivocal results, and one of the possible reasons for this finding might be due to relatively low maternal exposures. In addition, relatively narrow maternal exposure windows to PM_2.5 have not been well established for LBW.

Associations between short-term exposure to particulate matter and ultrafine particles and myocardial infarction in Augsburg,Germany

BackgroundShort-term exposure to increased particulate matter (PM) concentration has been reported to trigger myocardial infarction (MI). However, the association with ultrafine particles remains unclear.ObjectivesWe aimed to assess the effects of short-term air pollution and especially ultrafine particles on registry-based MI events and coronary deaths in the area of Augsburg, Germany.MethodsBetween 1995 and 2009, the MONICA/KORA myocardial infarction registry recorded 15,417 cases of MI and coronary deaths. Concentrations of PM < 10 μm (PM₁₀), PM < 2.5 μm (PM_2.5), particle number concentration (PNC) as indicator for ultrafine particles, and meteorological parameters were measured in the study region. Quasi-Poisson regression adjusting for time trend, temperature, season, and weekday was used to estimate immediate, delayed and cumulative effects of air pollutants on the occurrence of MI. The daily numbers of total MI, nonfatal and fatal events as well as incident and recurrent events were analysed.ResultsWe observed a 1.3% risk increase (95%-confidence interval: [−0.9%; 3.6%]) for all events and a 4.4% [−0.4%; 9.4%] risk increase for recurrent events per 24.3 μg/m³ increase in same day PM₁₀ concentrations. Nonfatal events indicated a risk increase of 3.1% [−0.1%; 6.5%] with previous day PM₁₀. No association was seen for PM_2.5 which was only available from 1999 on. PNC showed a risk increase of 6.0% [0.6%; 11.7%] for recurrent events per 5529 particles/cm³ increase in 5-day average PNC.ConclusionsOur results suggested an association between short-term PM₁₀ concentration and numbers of MI, especially for nonfatal and recurrent events. For ultrafine particles, risk increases were notably high for recurrent events. Thus, persons who already suffered a MI seemed to be more susceptible to air pollution.     

Effects of air pollution on exhaled nitric oxide in children: Results from the GINIplus and LISAplus studies

Most previous studies which have investigated the short-term effects of air pollution on airway inflammation, assessed by an increase of exhaled nitric oxide (eNO), have been conducted among asthmatic children. Few studies have considered this potential association among non-asthmatics. Furthermore, although both short- and long-term effects of air pollution on eNO had been reported separately, studies which include both are scarce. We explored associations between 24 h NO₂ and PM₁₀ (particles with aerodynamic diameters below 10 μm) mass with eNO in 1985 children (192 asthmatics and 1793 non-asthmatics) aged 10 years and accounted for the long-term effects of air pollution by adjusting for annual averages of NO₂, PM₁₀ mass, PM_2.5 mass (particles with aerodynamic diameters below 2.5 μm) and PM_2.5 absorbance, using data from two German birth cohorts in Munich and Wesel. In total, robust associations between 24 h NO₂ and eNO were observed in both single-pollutant (percentage change: 18.30%, 95% confidence interval: 11.63–25.37) and two-pollutant models (14.62%, 6.71–23.11). The association between 24 h PM₁₀ mass and eNO was only significant in the single-pollutant model (9.59%, 4.80–14.61). The same significant associations were also observed in non-asthmatic children, while they did not reach significant levels in asthmatic children. Associations between annual averages of ambient air pollution (NO₂, PM₁₀ mass, PM_2.5 mass and PM_2.5 absorbance) and eNO were consistently null. In conclusion, significantly positive associations were observed between short-term ambient air pollution and eNO. No long-term effects of air pollution on eNO were found in this study.     

The associations between traffic-related air pollution and noise with blood pressure in children: Results from the GINIplus and LISAplus studies

Although traffic emits both air pollution and noise, studies jointly examining the effects of both of these exposures on blood pressure (BP) in children are scarce. We investigated associations between land-use regression modeled long-term traffic-related air pollution and BP in 2368 children aged 10 years from Germany (1454 from Munich and 914 from Wesel). We also studied this association with adjustment of long-term noise exposure (defined as day–evening–night noise indicator “Lden” and night noise indicator “Lnight”) in a subgroup of 605 children from Munich inner city. In the overall analysis including 2368 children, NO₂, PM_2.5 mass (particles with aerodynamic diameters below 2.5 μm), PM₁₀ mass (particles with aerodynamic diameters below 10 μm) and PM_2.5 absorbance were not associated with BP. When restricting the analysis to the subgroup of children with noise information (N = 605), a significant association between NO₂ and diastolic BP was observed (−0.88 (95% confidence interval: −1.67, −0.08)). However, upon adjusting the models for noise exposure, only noise remained independently and significantly positively associated with diastolic BP. Diastolic BP increased by 0.50 (−0.03, 1.02), 0.59 (0.05, 1.13), 0.55 (0.03, 1.07), and 0.58 (0.05, 1.11) mmHg for every five decibel increase in Lden and by 0.59 (−0.05, 1.22), 0.69 (0.04, 1.33), 0.64 (0.02, 1.27), and 0.68 (0.05, 1.32) mmHg for every five decibel increase in Lnight, in different models of NO₂, PM_2.5 mass, PM₁₀ mass and PM_2.5 absorbance as the main exposure, respectively. In conclusion, air pollution was not consistently associated with BP with adjustment for noise, noise was independently and positively associated with BP in children.     

Associations between particulate matter elements and early-life pneumonia in seven birth cohorts: Results from the ESCAPE and TRANSPHORM projects

Evidence for a role of long-term particulate matter exposure on acute respiratory infections is growing. However, which components of particulate matter may be causative remains largely unknown. We assessed associations between eight particulate matter elements and early-life pneumonia in seven birth cohort studies (N_total = 15,980): BAMSE (Sweden), GASPII (Italy), GINIplus and LISAplus (Germany), INMA (Spain), MAAS (United Kingdom) and PIAMA (The Netherlands). Annual average exposure to copper, iron, potassium, nickel, sulfur, silicon, vanadium and zinc, each respectively derived from particles with aerodynamic diameters ≤ 10 μm (PM₁₀) and 2.5 μm (PM_2.5), were estimated using standardized land use regression models and assigned to birth addresses. Cohort-specific associations between these exposures and parental reports of physician-diagnosed pneumonia between birth and two years were assessed using logistic regression models adjusted for host and environmental covariates and total PM₁₀ or PM_2.5 mass. Combined estimates were calculated using random-effects meta-analysis. There was substantial within and between-cohort variability in element concentrations. In the adjusted meta-analysis, pneumonia was weakly associated with zinc derived from PM₁₀ (OR: 1.47 (95% CI: 0.99, 2.18) per 20 ng/m³ increase). No other associations with the other elements were consistently observed. The independent effect of particulate matter mass remained after adjustment for element concentrations. In conclusion, associations between particulate matter mass exposure and pneumonia were not explained by the elements we investigated. Zinc from PM₁₀ was the only element which appeared independently associated with a higher risk of early-life pneumonia. As zinc is primarily attributable to non-tailpipe traffic emissions, these results may suggest a potential adverse effect of non-tailpipe emissions on health.     

Second-hand smoke in hospitals in Catalonia (2009): a cross-sectional study measuring PM2.5 and vapor-phase nicotine

ObjectivesTo describe second-hand smoke in the hospitals of the Catalan Network for Smoke-free Hospitals using Particulate Matter (PM_2.5) and to assess the association between second-hand smoke exposure in main entrances (outdoors) and halls and between PM_2.5 and airborne nicotine concentrations.MethodsCross-sectional study carried out in 2009 in the 53 hospitals affiliated with the network. We measured PM_2.5 (μg/m³) in all hospitals and measured airborne nicotine concentrations (μg/m³) in a subsample of 11 hospitals. For each assessment, we measured nine locations within the hospitals, computing medians, means, geometric means, interquartile ranges (IQRs), and 95% confidence intervals (CI) of the means and the geometric means. Further, we used Spearman’s linear correlation coefficient r_sp) to explore the association between PM_2.5 concentrations in halls and main entrances and between PM_2.5 and nicotine concentrations.ResultsThe overall median of the 429 PM_2.5 measurements was 12.48 μg/m³ (IQR: 8.84–19.76 μg/m³). The most exposed locations were outdoor smoking points (16.64 μg/m³), cafeterias (14.82 μg/m³), and main entrances (14.04 μg/m³); dressing rooms were the least exposed (6.76 μg/m³). PM_2.5 concentrations in halls were positively correlated with those in main entrances (r_sp=0.591, 95% CI: 0.377–0.745), as were PM_2.5 values and nicotine concentrations (r_sp=0.644, 95% CI: 0.357–0.820).ConclusionsSecond-hand smoke levels in hospitals were low in most locations, with the highest levels observed in outdoor locations where smoking is allowed (smoking points and entrances). Smoking in main entrances was associated with increased second-hand smoke levels in halls. Use of PM_2.5 to evaluate second-hand smoke is feasible and shows a good correlation with airborne nicotine values.     

Chronic PM2.5 exposure and risk of infant bronchiolitis and otitis media clinical encounters

Chronic particulate matter less than 2.5 μm in diameter (PM_2.5) exposure can leave infants more susceptible to illness. Our objective is to estimate associations of the chronic PM_2.5 exposure with infant bronchiolitis and otitis media (OM) clinical encounters. We obtained all first time bronchiolitis (n = 18,029) and OM (n = 40,042) clinical encounters among children less than 12 and 36 months of age, respectively, diagnosed from 2001 to 2009 and two controls per case matched on birthdate and gestational age from the Pregnancy to Early Life Longitudinal data linkage system in Massachusetts. We applied conditional logistic regression to estimate odds ratios (OR) and confidence intervals (CI) per 2-μg/m³ increase in lifetime average satellite based PM_2.5 exposure_. Effect modification was assessed by age, gestational age, frequency of clinical encounter, and income. We examined associations between residential distance to roadways, traffic density, and infant bronchiolitis and OM risk. PM_2.5 was not associated with infant bronchiolitis (OR = 1.02, 95% CI = 1.00, 1.04) and inversely associated with OM (OR = 0.97, 95% CI = 0.95, 0.99). There was no evidence of effect modification. Compared to infants living near low traffic density, infants residing in high traffic density had elevated risk of bronchiolitis (OR = 1.23, 95% CI = 1.14, 1.31) but not OM (OR = 0.98, 95% CI = 0.93, 1.02) clinical encounter. We did not find strong evidence to support an association between early-life long-term PM_2.5 exposure and infant bronchiolitis or OM. Bronchiolitis risk was increased among infants living near high traffic density.     

Particulate matter air pollution,physical activity and systemic inflammation in Taiwanese adults

Background

The protective effects of physical activity (PA) against chronic disease can be partially ascribed to its anti-inflammatory effects. On the other hand, long-term exposure to particulate matter with an aerodynamic diameter less than 2.5 μm (PM_2.5) may induce systemic inflammation.

Is physical activity a modifier of the association between air pollution and arterial stiffness in older adults: The SAPALDIA cohort study

Introduction and objectives

Air pollution and insufficient physical activity have been associated with inflammation and oxidative stress, molecular mechanisms linked to arterial stiffness and cardiovascular disease. There are no studies on how physical activity modifies the association between air pollution and arterial stiffness. We examined whether the adverse cardiovascular effects of air pollution were modified by individual physical activity levels in 2823 adults aged 50–81 years from the well-characterized Swiss Cohort Study on Air Pollution and Lung and Heart Diseases (SAPALDIA).

Effect of long-term exposure to air pollution on anxiety and depression in adults: A cross-sectional study

Background

The association between exposure to air pollutants and mental disorders among adults has been suggested, although results are not consistent.

Effect of air pollution and racism on ethnic differences in respiratory health among adolescents living in an urban environment

Recent studies suggest that stress can amplify the harm of air pollution. We examined whether experience of racism and exposure to particulate matter with an aerodynamic diameter of less than 2.5 µm and 10 µm (PM_2.5 and PM₁₀) had a synergistic influence on ethnic differences in asthma and lung function across adolescence. Analyses using multilevel models showed lower forced expiratory volume (FEV₁), forced vital capacity (FVC) and lower rates of asthma among some ethnic minorities compared to Whites, but higher exposure to PM_2.5, PM₁₀ and racism. Racism appeared to amplify the relationship between asthma and air pollution for all ethnic groups, but did not explain ethnic differences in respiratory health.     

Association between PM10 concentrations and school absences in proximity of a cement plant in northern Italy

Dusts are one of the main air pollutants emitted during cement manufacturing. A substantial part of these are breathable particles that are less than 10 μm in diameter (PM₁₀), which represent a potential threat for the health of the exposed population. This study aimed at evaluating the short-term effects of PM₁₀ concentrations on the health of children, aged 6–14 years, who attended the schools in Fumane (Italy), in proximity (1.2 km) to a large cement plant. School absenteeism was used as a proxy indicator of child morbidity. Time series of daily school absences and PM₁₀ concentrations were collected for 3 school-years from 2007 to 2010 (541 school-days, 462 children on average). The associations between PM₁₀ concentrations and school absence rates in the same day (lag0) and in the following 4 days (lag1 to lag4) were evaluated using generalised additive models, smoothed for medium/long term trends and adjusted for day of the week, influenza outbreaks, daily temperature and rain precipitations. The average concentration of PM₁₀ in the period was 34 (range: 4–183) μg/m³. An average 10 μg/m³ increase of PM₁₀ concentration in the previous days (lag0–4) was associated with a statistically significant 2.5% (95%CI: 1.1–4.0%) increase in the rate of school absences. The highest increase in the absence rates (2.4%; 95%CI: 1.2–3.5%) was found 2 days after exposure (lag2). These findings provide epidemiological evidence of the acute health effects of PM₁₀ in areas with annual concentrations that are lower than the legal European Union limit of 40 μg/m³, and support the need to establish more restrictive legislative standards.     

Exposure to air pollution near a steel plant and effects on cardiovascular physiology: A randomized crossover study

BackgroundIron and steel industry is an important source of air pollution emissions. Few studies have investigated cardiovascular effects of air pollutants emitted from steel plants.ObjectiveWe examined the influence of outdoor air pollution in the vicinity of a steel plant on cardiovascular physiology in Sault Ste. Marie, Canada.MethodsSixty-one healthy, non-smoking subjects (females/males = 33/28, median age 22 years) spent 5 consecutive 8-hour days outdoors in a residential area neighbouring a steel plant, or on a college campus approximately 5 kilometres away from the plant, and then crossed over to the other site with a 9-day washout. Mid day, subjects underwent daily 30-minute moderate intensity exercise. Blood pressure (BP) and pulse rate were determined daily and post exercise at both sites. Flow-mediated vasodilation (FMD) was determined at the site near the plant. Air pollution was monitored at both sites. Mixed-effects regressions were run for statistical associations, adjusting for weather variables.ResultsConcentrations of ultrafine particles, sulphur dioxide (SO₂), nitrogen dioxide (NO₂) and carbon monoxide (CO) were 50–100% higher at the site near the plant than at the college site, with minor differences in temperature, humidity, and concentrations of particulate matter ≤2.5 μm in size (PM_2.5) and ozone (O₃). Resting pulse rate [mean (95% confidence interval)] was moderately higher near the steel plant [+1.53 bpm (0.31, 2.78)] than at the college site, male subjects having the highest pulse rate elevation [+2.77 bpm (0.78, 4.76)]. Resting systolic and diastolic BP and pulse pressure, and post-exercise BP and pulse rate were not significantly different between two sites. Interquartile range concentrations of SO₂ (2.9 ppb), NO₂ (5.0 ppb) and CO (0.2 ppm) were associated with increased pulse rate [0.19 bpm (−0.00, 0.38), 0.86 bpm (0.03, 1.68), and 0.11 bpm (0.00, 0.22), respectively], ultrafine particles (10,256 count/cm³) associated with increased pulse pressure [0.85 mmHg (0.23, 1.48)], and NO₂ and CO inversely associated with FMD [−0.14% (−0.31, 0.02), −0.02% (−0.03, −0.00), respectively]. SO₂ during exercise was associated with increased pulse rate [0.26 bpm (0.01, 0.51)].ConclusionAir quality in residential areas near steel plants may influence cardiovascular physiology.     

Can air pollution negate the health benefits of cycling and walking?

Active travel (cycling, walking) is beneficial for the health due to increased physical activity (PA). However, active travel may increase the intake of air pollution, leading to negative health consequences. We examined the risk–benefit balance between active travel related PA and exposure to air pollution across a range of air pollution and PA scenarios.The health effects of active travel and air pollution were estimated through changes in all-cause mortality for different levels of active travel and air pollution. Air pollution exposure was estimated through changes in background concentrations of fine particulate matter (PM_2.5), ranging from 5 to 200 μg/m3. For active travel exposure, we estimated cycling and walking from 0 up to 16 h per day, respectively. These refer to long-term average levels of active travel and PM_2.5 exposure.For the global average urban background PM_2.5 concentration (22 μg/m3) benefits of PA by far outweigh risks from air pollution even under the most extreme levels of active travel. In areas with PM_2.5 concentrations of 100 μg/m3, harms would exceed benefits after 1 h 30 min of cycling per day or more than 10 h of walking per day. If the counterfactual was driving, rather than staying at home, the benefits of PA would exceed harms from air pollution up to 3 h 30 min of cycling per day. The results were sensitive to dose–response function (DRF) assumptions for PM_2.5 and PA.PA benefits of active travel outweighed the harm caused by air pollution in all but the most extreme air pollution concentrations.     

Acute effects of urban air pollution on respiratory emergency hospital admissions in the Canary Islands

In the cities of Las Palmas (L/P) de Gran Canaria and Santa Cruz (S/C) de Tenerife, Canary Islands, particulate matter is highly influenced by mineral dust because their proximity to the Sahara desert (PM_10–2.5 levels are higher than PM_2.5). In this context, the short-term association between different PM fractions and gaseous pollutants with emergency hospital admissions for all respiratory, chronic obstructive pulmonary disease (COPD) and asthma was analyzed, evaluating the potential independent effect of PM_10–2.5. A generalized additive model was fitted controlling for seasonal patterns and time varying confounders. Different lag structures, polynomial distributed lag models, and two-pollutant models were examined. Under Lag01, in S/C de Tenerife, a 10 μg/m³ increase in PM_2.5 and PM_10–2.5 was associated with a 5.1 % risk increase (95 % confidence interval [CI] 1.0 to 9.2) in all respiratory and with a 7.7 % increase (95 % CI 0.9 to 14.9) in COPD emergency admissions, respectively. In L/P de Gran Canaria, a positive association between PM_10–2.5, PM_2.5, and NO₂ with the increased risk of asthma hospitalization was found: 11.2 % (95 % CI 0.5 to 22.9), 21.9 % (95 % CI 6.9 to 39.0), and a 17.4 % (95 % CI 6.6 to 29.4), respectively. The overall findings suggest that in these cities, (1) PM_2.5, PM_10–2.5, and NO₂ are associated with the risk of emergency hospital admission for respiratory diseases; (2) there is no evidence of confounding for the associations observed; and (3) PM_10–2.5 may have an impact on public health.     

Respiratory hospitalizations of children living near a hazardous industrial site adjusted for prevalent dust: A case–control study

The Neot Hovav Industrial Park (IP), located in southern Israel, hosts 23 chemical industry facilities and the national site for treatment of hazardous waste. Yet, information about its impact on the health of local population has been mostly ecological, focused on Bedouins and did not control for possible confounding effect of prevalent dust storms. This case–control study examined whether living near the IP could lead to increased risk of pediatric hospitalization for respiratory diseases. Cases (n = 3608) were residents of the Be’er Sheva sub-district aged 0–14 years who were admitted for respiratory illnesses between 2004 and 2009. These were compared to children admitted for non-respiratory conditions (n = 3058). Home addresses were geocoded and the distances from the IP to the child's residence were calculated. The association between hospitalization and residential distance from the IP was examined for three age groups (0–1, 2–6, 7–14) by logistic regressions adjusting for gender, socioeconomic status, urbanity and temperature. We found that infants in the first year of life who lived within 10 km of the IP had increased risk of respiratory hospitalization when compared with those living >20 km from the IP (adjusted odds ratio, OR = 2.07, 95% confidence interval, CI: 1.19–3.59). In models with both distance from the IP and particulate matter with aerodynamic diameter <10 μm (PM₁₀) the estimated risk was modestly attenuated (OR = 1.96, 95% CI: 1.09–3.51). Elevated risk was also observed for children 2–5 years of age but with no statistical significance (OR = 1.16, 95% CI: 0.76–1.76). Our findings suggest that residential proximity to a hazardous industrial site may contribute to early life respiratory admissions, beyond that of prevailing PM₁₀.     

Long-Term Exposure to Urban Air Pollution and Mortality in a Cohort of More than a Million Adults in Rome

Background: Few European studies have investigated the effects of long-term exposure to both fine particulate matter (≤ 2.5 µm; PM_2.5) and nitrogen dioxide (NO₂) on mortality.Objectives: We studied the association of exposure to NO₂, PM_2.5, and traffic indicators on cause-specific mortality to evaluate the form of the concentration–response relationship.Methods: We analyzed a population-based cohort enrolled at the 2001 Italian census with 9 years of follow-up. We selected all 1,265,058 subjects ≥ 30 years of age who had been living in Rome for at least 5 years at baseline. Residential exposures included annual NO₂ (from a land use regression model) and annual PM_2.5 (from a Eulerian dispersion model), as well as distance to roads with > 10,000 vehicles/day and traffic intensity. We used Cox regression models to estimate associations with cause-specific mortality adjusted for individual (sex, age, place of birth, residential history, marital status, education, occupation) and area (socioeconomic status, clustering) characteristics.Results: Long-term exposures to both NO₂ and PM_2.5 were associated with an increase in nonaccidental mortality [hazard ratio (HR) = 1.03 (95% CI: 1.02, 1.03) per 10-µg/m³ NO₂; HR = 1.04 (95% CI: 1.03, 1.05) per 10-µg/m³ PM_2.5]. The strongest association was found for ischemic heart diseases (IHD) [HR = 1.10 (95% CI: 1.06, 1.13) per 10-µg/m³ PM_2.5], followed by cardiovascular diseases and lung cancer. The only association showing some deviation from linearity was that between NO₂ and IHD. In a bi-pollutant model, the estimated effect of NO₂ on mortality was independent of PM_2.5.Conclusions: This large study strongly supports an effect of long-term exposure to NO₂ and PM_2.5 on mortality, especially from cardiovascular causes. The results are relevant for the next European policy decisions regarding air quality.     

Occupational exposure to particulate matter from three agricultural crops in California

Agricultural work is a major contributor to California's and the nation's economy and employs a large number of workers. However, agricultural work can have numerous risks, such as exposure to elevated levels of particulate matter (PM) and other airborne pollutants with potential adverse health effects. To determine the magnitude of occupational exposures, PM levels were assessed for 89 workers from three major crops in California; almonds, melons and tomatoes. Personal samples were collected for PM_2.5 and inhalable PM using personal sampling equipment. Geometric mean concentrations from personal exposure for workers in almonds (inhalable PM = 4368 μg/m³, PM_2.5 = 122 μg/m³, N = 5), tomatoes (inhalable PM = 1410 μg/m³, PM_2.5 = 12 μg/m³, N = 33), and melons (inhalable PM = 1118 μg/m³, PM_2.5 = 19 μg/m³, N = 51) showed high PM exposure when working with these three crops. Large exposure differences by crop were more common than by task (i.e. harvesting, packing and weeding) among the three crops studied. This is the largest study of agricultural workers engaged in hand harvesting, a significant employer of farm labor, and relatively high levels of exposure to PM were measured.