Personal exposure to black carbon at school and levels of fractional exhaled nitric oxide in new york city

BACKGROUND: Schools are often located near traffic sources, leading to high levels of exposure to traffic-related air pollutants, including black carbon (BC). Thus, the school environment could play in a significant role in the adverse respiratory health of children. OBJECTIVES: Our objective was to determine associations between personal BC levels at school and airway inflammation [i.e., fractional exhaled ni-tric oxide (FeNO)] in school-age children. We hypothesized that higher school BC (SBC) would be associated with higher FeNO. METHODS: Children 9–14 years of age in New York City (NYC) (n = 114) wore BC monitors for two 24-h periods over a 6-d sampling period, repeated 6 months later. SBC was defined as the average personal BC concentrations measured during NYC school hours (i.e., 0830–1430 hours). FeNO was measured following each 24-h BC monitoring period. Multivariable linear regression in generalized estimating equation models were used to examine associations between SBC and FeNO. Results are presented as percentage difference (PD) in FeNO. RESULTS: Personal BC at school was associated with higher FeNO (PD = 7:47% higher FeNO per 1-μg/m³ BC (95% CI: 1.31, 13.9), p = 0:02]. Compared with BC exposure during school, a smaller PD in FeNO was observed in association with BC exposure while commuting to and from school [PD = 6:82% (95% CI: 0.70, 13.3), p = 0:03]. Personal BC in non-school environments and residential BC were not associated with FeNO (p >0:05). A significant association between personal BC at school and FeNO was observed among children with seroatopy who did not have asthma [PD = 21:5% (95% CI: 4.81, 40.9), p = 0:01]. DISCUSSION: Schools may be important sources of BC exposure that contribute to airway inflammation in school-age children. Our results provide ra-tionale for interventions that target improved air quality in urban schools and classrooms. https://doi.org/10.1289/EHP8985.