The Relationship Between PM2.5 and the Action Spectrum of Ultraviolet Radiation for Vitamin D Production Based On a Manikin Model
Objectives: Fine particulate matter (PM 2.5 ) is the principal air pollutant and poses a serious threat to public health. This study explored the effects of PM 2.5 on the action spectrum of ultraviolet radiation for vitamin D production (UV vitD ) received by manikin surfaces. Methods: Multi-inclination angle ultraviolet radiation monitoring was conducted with different concentrations of PM 2.5 . Combining monitoring data with the PM 2.5 concentration, solar elevation angle (SEA), and
... n angle, a UV vitD exposure model for human body multi-inclined surfaces was constructed through a multiple linear regression analysis. A 3D manikin model was used to examine the PM 2.5 effects on UV vitD received by the manikin surface. Results: When PM 2.5 concentrations ranged from 35 μg/m 3 to 100 μg/m 3 (average concentration of PM 2.5 in this range: 62 μg/m 3 ), the UV vitD received by the whole body was reduced by approximately 8.45% to 19.82% compared with the UV vitD received when PM 2.5 concentrations ranged from 6 μg/m 3 to 35 μg/m 3 (average concentration of PM 2.5 in this range: 17 μg/m 3 ) with SEAs between 30° and 50°. Moreover, the UV vitD dose was reduced by 11.82% in the above comparisons. When further comparing PM 2.5 concentrations from 100 μg/m 3 to 161 μg/m 3 (average concentration of PM 2.5 in this range: 132 μg/m 3 ) with those from 6 μg/m 3 to 35 μg/m 3 (average concentration of PM 2.5 in this range: 17 μg/m 3 ), the UV vitD received by the whole body was reduced by approximately 21.6% to 50.64% at SEAs between 30° and 50°. The UV vitD dose was reduced by 30.2%. Conclusions: The occurrence of PM 2.5 obviously reduced the UV vitD received by the manikin surface. INDEX TERMS PM 2.5 ; Ultraviolet radiation; Manikin model; Inclination angle; Vitamin D VOLUME XX, 2017 1 . Multiple studies indicate that both long-and short-term exposure to particulate matter (PM) is associated with the increased morbidity and mortality of chronic diseases, such as respiratory and cardiovascular diseases [28-31]. Fine particulate matter (PM 2.5 ) is considered the most dangerous among all PM  and can penetrate deep into human lungs and even into the blood because of its small size ,  . A 10 μg/m 3 increase in exposure to PM 2.5 is associated with an 11% increase in cardiovascular mortality  . Exposure to PM 2.5 is also associated with an increased risk of hypertension  . Therefore, air pollution not only directly harms human health but also reduces vitamin D synthesis by decreasing ultraviolet radiation intensity. This harmful double impact of air pollution deserves significant attention. Latitude and season influence the production of vitamin D3 in human skin, and vitamin D3 is converted from 7dehydrocholesterol in the skin after UV radiation and thermal processing, which further affects the vitamin D status in the human body    . 25(OH)D (the main storage form of vitamin D in the human body) levels decrease with increasing latitude  . The National Diet and Nutrition Survey even indicated that in areas higher than 40° N latitude, the synthesis of vitamin D in the skin from October to March was reduced due to insufficient UV radiation  . In addition to the effects of latitude and season on vitamin D, air pollution is found to indirectly inhibit vitamin D synthesis by directly reducing ultraviolet radiation. Therefore, air pollution has a significant impact on public health, especially for high-risk groups living in middle and high latitudes who are prone to vitamin D deficiency. The associations between the action spectrum of ultraviolet radiation for vitamin D production (UV vitD ) and PM 2.5 , the solar elevation angle (SEA), and the inclination angle were examined using a homemade multiangle UV monitoring model and multiple linear regression analysis. Moreover, a 3D manikin model was also used to assess the impact of PM 2.5 on the UV vitD received by the manikin surface. This work presents the most comprehensive study of the relationship between PM 2.5 and UV vitD to date, and it aims to draw more attention to the risks of PM 2.5 , especially among groups vulnerable to vitamin D deficiency.