Indoor air formaldehyde (HCHO) pollution of urban coach cabins

Abstract

Urban coach cabin is an important indoor environment for long journey, formaldehyde (HcHo) is a carcinogenic gas and damages indoor air quality of cabins. in order to control the HcHo pollution, the air samples inside cabins were analysed with a thermally desorbed gas chromatograph, and the HcHo diffusion was simulated with a methodology of computational fluid dynamics (CFD). Results show that through the experimental monitoring, the HCHO pollution level range from 33.6 to 142.3 μg/m 3 , decrease quickly with time, and the attenuation trendline is univariate cubic equation. through the cfD simulation, the indoor temperature and HcHo level of cabin front and rear ends are higher than ones of other areas for the insufficient air supply and the unreasonable arrangement of air exhaust outlet. Moreover, through the cfD simulation, the HcHo level decreases with height growth of breathing zone and increasing air supply speed, and fresh air lead to diffusion of HCHO pollution from cabin seat area to the surrounding area. through the cfD simulation, the HcHo pollution under the wind speeds of 3~5 m/s is higher than the HCHO limit level from indoor air standard of China vehicles, which shows that the HcHo emission of cabin seat has an important impact on airborne HcHo pollution inside vehicle cabins. According to the year 2017 statistic bulletin of traffic industry development from the Transportation Ministry of China, the total of urban vehicles was 3.1 × 10 8 and the annual capacity of passengers transported by the vehicles was 7.2 × 10 11. For people often go working, shopping, traveling, school, home and lengthy commutes by driving or taking a vehicle such as a car, taxi, bus or coach, vehicle cabins have been recognized as important indoor environment, which result into indoor air quality (IAQ) and thermal comfort of vehicle cabins to be a hot research 1-8. However, vehicle cabins have presented airborne formaldehyde (HCHO) and volatile organic compounds (VOCs) pollution, which damage vehicle IAQ 9-15. For example, more than 260 VOCs 16 were detected in the vehicle cabins and the maximum level of total VOCs was 6.90 mg/m 3. Moreover, the HCHO pollution was relatively abundant in the coach cabins, and the HCHO highest level of 0.16 mg/m 3 was observed on the 15th day after coming off the assembly line 11. Except to pollute vehicle IAQ, the HCHO and VOCs pollution lead to the unacceptable health risks to passengers and drivers 17-19. In order to decrease the health risks, China government promulgated the hygienic standard for air quality inside long distance coach (GB/T 17729-2009) and the guideline for air quality assessment of passenger car (GB/T 27630-2011), with the HCHO limit levels of 0.12 and 0.10 mg/m 3 respectively. However, the average/maximal HCHO levels in car cabins were 132.0/251.6 μg/m 3 , which were 1.10/2.10 and 1.32/2.52 times more than the HCHO limit levels of IAQ standards on China coaches (GB/T 17729-2009) and passenger cars (GB/T 27630-2011) respectively 20. The HCHO average level in taxi cabins wa...

Assessment of the mutagenicity of two common indoor air pollutants, formaldehyde and toluene

“…Notably, as individuals often remain indoors longer than outdoors, HCHO pollution indoors must be reduced to avoid potential detrimental effects on human health. Vehicle cabins have been recognized as important indoor environments, and recent reports have shown that the indoor air quality of vehicle cabins is easily polluted by various VOCs (such as toluene) and HCHO 45–47 . Individuals should thus increase the rate of indoor ventilation and cabin, particularly after introducing new sources of HCHO inside, and decrease HCHO pollution indoors or in cabins.…”

Simulation and measurement of air quality in the traffic congestion area

“…For example, Wang et al [18] recommended the optimal deflect angle for tunnel ventilation using CFD. Qin et al [19] recommended the numerical simulation of airborne HCHO pollution in vehicle cabins using CFD. Through CFD simulation, it can be an accurate prediction of air pollution flow properties and species transport [20][21][22].…”

Comparison of formaldehyde measurements by Hantzsch, CRDS and DOAS in the SAPHIR chamber

“…For the experiments in this work, the instrument was placed in an air-conditioned sea container next to the chamber. Parts of the instrument were temperature stabilized: the stripping coil at 283 K, the reaction volume at 341 K and the fluorimeter at 308 K. This ensured that the reaction efficiency and fluorescence detection sensitivity remained approximately constant (Rurack and Spieles, 2011;Resch-Genger and Rurack, 2013). The tubing of the peristaltic pumps was exchanged every 2 weeks due to tube degradation and in order to prevent occlusions or a major loss of pumping performance, which could cause the instrument sensitivity to change by up to 10 % within this time span (Sect.…”

“…Formaldehyde (HCHO) is a pollutant that is present in ambient air but also indoors. It affects human health by irritating the respiratory system and by being carcinogenic (Gupta et al, 1982;Casset et al, 2005;World Health Organization, 2010;Fortems-Cheiney et al, 2012;Liu et al, 2015;Salthammer, 2019;Qin et al, 2020). It is formed in the atmosphere as a product of the oxidation of volatile organic compounds (VOCs) and in combustion processes, includ-ing biomass burning.…”