More than 10 million people commute extremely: some people commute for 3 hours each way, commute for more than 20 minutes, and the chance of cancer is as high as 10%

What is the commute distance and time to work each day?

According to the "2022 China Major Cities Commuting Monitoring Report" released by the China Academy of Urban Planning and Design, a happy commute within 5 kilometers and a one-way commute of more than 60 minutes is called "extreme commuting"
.

It was found that more than 14 million people in 44 cities experienced extreme commuting, with nearly 6 million young people
.
In 44 major cities in the country, 13%
commute time is more than 60 minutes each way.

A few days ago, there were media reports that an office worker commuting from Xiaoshan to Yuhang needed 23 subway stations and reserved a 3-hour round
trip.
A post-95 girl, it takes 3 hours to commute from the town to the city by bus, and if you miss a trip, you need to wait another 20 minutes
.

Not long ago, 021 video reported that a girl surnamed Jin, who lives in Zhujing Town, Jinshan District, Shanghai, works in Yangpu District Wangu Science and Technology Park, 100 kilometers one way, and her daily commute takes 6.
5 hours to go back and forth, and she gets up at 5:20 a.
m.
to catch up with work at 9 a.
m
.

Although there is a car, the highway fee + fuel fee + parking fee in January costs 5,000 yuan, the salary is not affordable, and in the morning and evening peaks, it takes nearly 2 hours
one way.

It is understood that in 2021, Beijing commuting has the largest spatial scale, with a radius of 41 kilometers
.

In California, USA, more than 1.
5 million people commute more than 2 hours a day, and 3% of the population commutes more than 3 hours
a day.
Longer commutes can be harmful to health, while people who spend longer hours in a car may be exposed to higher concentrations of hazardous substances (CO, volatile organic compound VOCs, ozone, and flame retardants), and a significant proportion of people in California may inhale benzene and formaldehyde beyond safe limits
.

A study published today in Environment International showed that in California, 78% of commuters have at least a 10% chance of developing cancer from exposure to benzene; 63% of commuters have at least a 10% chance of developing cancer
from exposure to formaldehyde.

AalekhyaReddam et al.
Inhalation of two Prop 65-listed chemicals within vehicles may be associated with increased cancer risk.
Environment International.
DOI：10.
1016 / j.
envint.
2021.
106402

California Proposition 65 (Prop 65) lists
chemicals that may cause cancer, birth defects, and reproductive harm.
Several chemicals from Prop 65 were detected in the vehicle: benzene, formaldehyde, diphthalate (DEHP), dibutyl phthalate (DBP), triphosphate (TDCIPP), diisodecyl phthalate (DIDP) and diisononyl phthalate (DINP).

Both benzene and formaldehyde are volatile organic compounds that are easily emitted into the air
.
Formaldehyde is often used in carpets, leather and paints in cars, and the high concentration of benzene in cars is inseparable
from fuel and exhaust emissions.
David Volz, professor of environmental toxicology at UCLA, said: "These chemicals are very volatile and easily transferred to the air
you breathe.
”

Researchers at the University of California, Riverside, believe that the presence of benzene and formaldehyde in the air poses a higher
health threat to office workers than interior items indicate the detection of hazardous substances.
They detected benzene and formaldehyde from the interior air, DEHP, DBP and TDCIPP detected in the dust in the car, and the median daily doses of formaldehyde and benzene inhaled from the car air were 379.
51 and 161.
97 μg/day
, respectively.
The median daily doses of DEHP, DBP and TDCIPP ingested from in-vehicle dust were 9.
77, 0.
236 and 0.
06 μg/day
, respectively.

DBP, DEHP and TDCIPP are semi-volatile organic compounds (SVOCs) that are more easily adsorbed on the surface of
dust particles, furniture materials, plastics and other items.
DEHP and DBP are mainly used for automotive seat fabrics and interior and exterior decoration
.

TDCIPP is a commonly used flame retardant used to make vehicle instrument panels
.
A two-year study of chronic toxicity in mice showed that for TDCIPP, the oral intake of NSRL was 5.
4 μg/day (the amount of chemicals that may cause cancer is labeled with NSRL, NSRL indicates that exposure to chemicals in a product results in no more than one cancer patient per 100,000 cancer patients), and that daily intake of TDCIPP from the diet during the year may lead to liver, kidney and testicular tumors.
The dose of TDCIPP correlates
with the incidence of cancer.

Estimated daily dose (μg/day) for TDCIPP, DBP, and DEHP inhalation, and estimated daily dose for 24-hour air intake of benzene and formaldehyde (μg/day).

Assuming an adult spends 20 minutes in the car every day, the median estimated doses of formaldehyde, benzene, DEHP, DBP, and TDCIPP are 5.
27, 2.
25, 0.
14, 0.
003, and 0.
0008 μg/day, respectively, and this dose increases over time
.
When staying in the car for 240 minutes (4 hours), the estimated median doses of formaldehyde, benzene, DEHP, DBP and TDCIPP were 63.
25, 27, 1.
63, 0.
04 and 0.
01 μg/day, respectively, from these values, it can be seen that the concentration of chemicals in the air inside the car is higher
than in dust.

With commuting time, the daily dose (μg/day) of chemicals found in dust (A) and air (B) in the car is distributed

According to California regulations, the reference value for the daily dose of a particular chemical substance is expressed as RfDs%, and the probability of exceeding the standard is used as a function of the reference value of the daily dose, when RfD%>100 indicates that the daily dose of the ingested chemical exceeds the safe range, and the probability of RfD%>100 depends on the type of chemical and commute time
.
Benzene and formaldehyde are both RfD%>100 chemicals
.

Cancer risk associated with benzene (A) or formaldehyde (B) exposure

Excess probability curve for reproductive and developmental toxicity risk (MADL) associated with benzene exposure (C)

The probability of RfD%>100 of three chemical substances as a function of commuting time (D)

Levels of chemicals that have the potential to cause reproductive and developmental toxicity are labeled
with MADL.
MADL says that even if an individual is exposed to 1,000 times that level, it will not work
chemically.

The study authors believe that the risk of benzene-related cancer, in the case of a commute time of 20-240 minutes, the probability of RfD%>100 ranges from 2.
4% ~ 77.
5%; The probability of cancer risk related to formaldehyde ranges from 0.
9%~74.
4
% to RfD%>100.
In addition, the risk of reproductive toxicity of benzene is also much lower than the risk
of cancer of benzene or formaldehyde.

Researchers believe that emissions of these VOCs may decrease with vehicle age, total vehicle mileage, ventilation rate, and decrease in vehicle temperature or relative humidity, and measures can be taken to reduce the daily dose
of hazardous substances inhaled by commuters.

Reddam advises commuters to keep windows open as much as possible during their ride
.
"At least with air circulating, you're diluting the concentration
of these chemicals in the car," she said.
”

"There should be alternatives to these chemicals, and we should be using alternatives
," Volz said.
”

In many regions, vehicle emissions have become a major source of air pollutants, including carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds or hydrocarbons (hc), nitrogen oxides (NOx), and particulate matter (PM).

Increasing traffic congestion can significantly increase emissions of these pollutants and reduce air quality
.
According to epidemiological studies, the emission of pollutants increases the risk
of morbidity and mortality among drivers, commuters, and individuals living near highways.

Over the next decade, due to continued urbanization, more and more of the population may be affected by transport-related emissions (black smoke, ozone, etc.
), and even increase the risk
of non-allergic respiratory infections and inflammation.