Estimating population exposure to ambient polycyclic aromatic hydrocarbon in the United States - Part II: Source apportionment and cancer risk assessment.
A revised Community Multiscale Air Quality (CMAQ) model was developed to simulate the emission, reactions, transport, deposition and gas-to-particle partitioning processes of 16 priority polycyclic aromatic hydrocarbons (PAHs), as described in Part I of the two-part series. The updated CMAQ model was applied in this study to quantify the contributions of different emission sources to the predicted PAH concentrations and excess cancer risk in the United States (US) in 2011. The cancer risk in the continental US due to inhalation exposure of outdoor naphthalene (NAPH) and seven larger carcinogenic PAHs (cPAHs) was predicted to be significant. The incremental lifetime cancer risk (ILCR) exceeds 1×10-5in many urban and industrial areas. Exposure to PAHs was estimated to result in 5704 (608-10,800) excess lifetime cancer cases. Point sources not related with energy generation and the oil and gas processes account for approximately 31% of the excess cancer cases, followed by non-road engines with 18.6% contributions. Contributions of residential wood combustion (16.2%) are similar to that of transportation-related sources (mostly motor vehicles with small contributions from railway and marine vessels; 13.4%). The oil and gas industry emissions, although large contributors to high concentrations of cPAHs regionally, are only responsible of 4.3% of the excess cancer cases, which is similar to the contributions of non-US sources (6.8%) and non-point sources (7.2%). The power generation units pose the most minimal impact on excess cancer risk, with contributions of approximately 2.3%.
Zachary Depart of Civil Engineering, Texas A&M University, College Station, TX 77845, United States.
Jie
J
Zhang
Zachary Depart of Civil Engineering, Texas A&M University, College Station, TX 77845, United States.
Peng
P
Wang
Zachary Depart of Civil Engineering, Texas A&M University, College Station, TX 77845, United States.
Jingyi
J
Li
Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, United States.
Pauline
P
Mendola
The Emmes Corporation, Rockville, MD 20850, United States.
Seth
S
Sherman
Zachary Depart of Civil Engineering, Texas A&M University, College Station, TX 77845, United States. Electronic address: qying@civil.tamu.edu.
Qi
Q
Ying
D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution; D002273:Carcinogens / Q000633:toxicity*; D002947:Cities; D004784:Environmental Monitoring; D006801:Humans; D019570:Inhalation Exposure; D008962:Models, Theoretical; D009281:Naphthalenes / Q000633:toxicity*; D009369:Neoplasms / Q000139:chemically induced*; D000066388:Oil and Gas Industry; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D018570:Risk Assessment; D014481:United States
D000393:Air Pollutants; D002273:Carcinogens; D009281:Naphthalenes; D011084:Polycyclic Aromatic Hydrocarbons
Benzo[α]pyrene; Cancer risk assessment; Polycyclic aromatic hydrocarbon; Source apportionment; United States