Motor vehicle emissions usually constitute the most significant source of ultrafine particles (diameter <0.1 microm) in an urban environment, yet little is known about the concentration and size distribution of ultrafine particles in the vicinity of major highways. In the present study, particle number concentration and size distribution in the size range from 6 to 220 nm were measured by a condensation particle counter (CPC) and a scanning mobility particle sizer (SMPS), respectively. Measurements were taken 30, 60, 90, 150, and 300 m downwind, and 300 m upwind, from Interstate 405 at the Los Angeles National Cemetery. At each sampling location, concentrations of CO, black carbon (BC), and particle mass were also measured by a Dasibi CO monitor, an aethalometer, and a DataRam, respectively. The range of average concentration of CO, BC, total particle number, and mass concentration at 30 m was 1.7-2.2 ppm, 3.4-10.0 microg/m3, 1.3-2.0 x 10(5)/cm3, and 30.2-64.6 microg/m3, respectively. For the conditions of these measurements, relative concentrations of CO, BC, and particle number tracked each other well as distance from the freeway increased. Particle number concentration (6-220 nm) decreased exponentially with downwind distance from the freeway. Data showed that both atmospheric dispersion and coagulation contributed to the rapid decrease in particle number concentration and change in particle size distribution with increasing distance from the freeway. Average traffic flow during the sampling periods was 13,900 vehicles/hr. Ninety-three percent of vehicles were gasoline-powered cars or light trucks. The measured number concentration tracked traffic flow well. Thirty meters downwind from the freeway, three distinct ultrafine modes were observed with geometric mean diameters of 13, 27, and 65 nm. The smallest mode, with a peak concentration of 1.6 x 10(5)/cm3, disappeared at distances greater than 90 m from the freeway. Ultrafine particle number concentration measured 300 m downwind from the freeway was indistinguishable from upwind background concentration. These data may be used to estimate exposure to ultrafine particles in the vicinity of major highways.

https://www.marincounty.org/depts/cd/divisions/planning/environmental-review/eir-archived-projects/~/media/Files/Departments/CD/Planning/Environmental%20Impact/Big%20Rock/supplemental/38_Zhu_2002_Concentration_and_Size_Distribution_of_Ultrafine_Particles_near_a_Major_Highway.pdf

Concentration and Size Distribution of Ultrafine Particles Near a Major Highway

http://mail.ictf-jpa.org/publiccomment/Documents/Zhu%202002%20710Fwy.pdf

Study of ultrafine particles near a major highway with heavy-duty diesel traffic

Ambient nano and ultrafine particles from motor vehicle emissions: Characteristics, ambient processing and implications on human exposure

Concentrations of submicrometre particles from vehicle emissions near a major road

In this paper, recent reviews of the World Health Organization, other review papers, and more recent literature on the human health effects of current air pollution trends in urban areas are reviewed and summarized as follows: Sulphur dioxide. Some studies, but not others, found associations between sulphur dioxide (SO2) exposure and daily mortality and morbidity. Single-pollutant correlations sometimes disappeared when other pollutants, especially suspended particulate matter (SPM), were included. Cross-sectional studies with asthmatics revealed significant, non-threshold relations between SO2 and decrements of the forced expiratory volume in 1 second (FEV1). Nitrogen dioxide. Weak associations between short-term nitrogen dioxide (NO2) exposure from gas cooking and respiratory symptoms and a decrement in lung function parameters were found in children, but not consistently in exposed women. With long-term exposure, children, but not adults, exhibit increased respiratory symptoms, decreased lung function, and increased incidences of chronic cough, bronchitis, and conjunctivitis. A causal relationship between NO2 exposure and adverse health effects has not yet been established. Carbon monoxide. Binding of CO in the lungs with hemoglobin in the blood forms carboxyhemoglobin (COHb), which impairs the transport of oxygen. The health effects of CO include hypoxia, neurological deficits and neurobehavioral changes, and increases in daily mortality and hospital admissions for cardiovascular diseases. The latter persists even at very low CO levels, indicating no threshold for the onset of these effects. Whether the relation between daily mortality and exposure to CO are causal or whether CO might act as a proxy for SPM is still an open question. Ambient CO may have even more serious health consequences than does COHb formation and at lower levels than that mediated through elevated COHb levels. Ozone. Short-term acute effects of O3 include pulmonary function decrements, increased airway responsiveness and airway inflammation, aggravation of pre-existing respiratory diseases like asthma, increases in daily hospital admissions and emergency department visits for respiratory causes, and excess mortality. Exposure-response relations are non-linear for the respective associations between O3 and FEV1, inflammatory changes, and changes in hospital admissions, whereas the relation between percent change in symptom exacerbation among adults and asthmatics is linear. Single-pollutant associations between O3 exposure and daily mortality and hospital admissions for respiratory diseases is statistically significant, even in multi-pollutant models. Suspended particulate matter. Associations between SPM concentrations and mortality and morbidity rates are significant. The acute health effects of SPM, even at short-term low levels of exposure, include increased daily mortality and hospital admission rates for exacerbation of respiratory disease, fluctuations in the prevalence of bronchodilator use, and cough and peak flow reductions, as well as long-term effects with respect to mortality and respiratory morbidity. Such effects depend on particle size and concentration and can fluctuate with daily fluctuations in PM10 or PM2.5 levels. The relation between PM10 or PM2.5 exposure and acute health effects is linear at concentrations below 100 micrograms/m3. Currently no threshold has been reported below which no effects occur. The influence of co-polluting gaseous pollutants could explain part of the observed variance in short-term health effects and reduce the contribution of SPM. Lead. The biological effects of lead can be related to blood lead levels, the best indicator of internal exposure. The potential effects of lead in adults and children include encephalopathic signs and symptoms, central nervous system symptoms, cognitive effects, increased blood pressure, and reduced measures of child intelligence. (ABSTRACT TRUNCATED)

Donald Neale

Papers

Comprehensive characterization of aerosols in a subtropical urban atmosphere : Particle size distribution and correlation with gaseous pollutants

Low-cost sensors as an alternative for long-term air quality monitoring.

Air quality during and after the Commonwealth Games 2018 in Australia: multiple benefits of monitoring