Contemporary Economic Challenges B 2 - Air Pollution

Question 1

What is the main health impact of air pollution?

Answer 1

• Probably the most obvious – breathing polluted air is a risk factor in many diseases, especially cardio-pulmonary
• Very major contributor to total mortality. Also corresponding
  morbidity burden

Question 2

Describe, with varying references, the sources of air pollution and how many people die from air pollution each year

Answer 2

• ‘All sources’ includes both anthropogenic and natural sources
• The largest source of natural air pollution is airborne dust in the world’s deserts. Other natural sources are fires, sea spray, pollen and volcanoes.
• Anthropogenic sources include electricity production: the burning of solid fuels for cooking and heating in poor households; agriculture; industry; and cold transport
• WHO (2021) says 7M in 2016, 4.2 from outdoor air pollution and 3.8 from indoor
• Institute for Health Metrics and Evaluation (2021) says 6.7M in 2019, 4.5 from outdoor and 2.3 from indoor
• Lelieveld et al. (2019) says 8.8M in 2015, 5.5 from anthropogenic sources and 3.6 from fossil fuels.

Question 3

Describe the distribution of impact of air pollution and what can be done to prevent it

Answer 3

• Very uneven impact – burden tends to be on poor
  countries, and on poorer communities within countries.
• Policy objectives can involve reducing averages, but also
  reducing inequalities

Question 4

Describe disease burden and its distribution

Answer 4

According to ‘Our World in Data (2019)’, disease burden is measured in disability-adjusted life years (DALYs). DALYs are age-standardised and therefore adjust for changes in age structures of population thrugh time and across countries.

In 2019, disease burden from particulate pollution was prevalent in most of the world apart from western europe, australia and north america, where they all exceeded 250 of a possible 10k. It was most concentrated in India, Mongolia, the Middle East (where figures exceeded 2500) and different parts of Africa.

Question 5

Describe the economic impact of air pollution

Answer 5

• Health impacts impose direct costs on economy –
  healthcare, work absence, etc..
• But also social impact not captured by e.g. GDP: people like
  being alive! And like being healthy!
• Appropriate accounting for that in a cost-benefit framework
  requires non-market valuation of VOSL and/or QALY/DALY.

Question 6

Describe & explain using natural experiments/quasi-experiments to
think about causal impact of pollution on health

Include why we need to do this

Answer 6

Using natural experiments/quasi-experiments to
think about causal impact of pollution on health
* Why do we need this? Problems with looking at associations.
* Economists often try to use methods sketched last week to isolate the
causal component of correlations.
- A few examples below
* Search for naturally occurring phenomena that generate plausibly
exogenous variations in ‘treatment’.
* Note importance of different time horizons, and different outcomes
* Examples
1. Zhong et al. (2017):
* How does short-term (say daily) variations in air pollution causally
impact health outcomes, such as hospital admissions?
* What would the perfect experiment look like?
- The perfect experiment: Take one city and some days, at random, there’ll be a pollution tap that will be switched on and we will see how many people go to hospital. Then compare this to days where the tap is off.
* Not feasible: Need to find a quasi- or natural experiment.
- Instrumental Variables (IV) method very common. An instrument is something that causes the independant variable to change without researchers manually doing it themselves.
- In China, 4 is considered an unlucky number. They have a policy to limit cars in the city centre by giving days to certain cars depending on the last number on their license plate. Because 4 is such an unlucky number, very few people don’t have their cars’ license plate ending in 4. Therefore, on days where the government bans cars with license plates ending in 4’, there’s 22% more congestion on the road – this is very similar to ‘turning the pollution tap on’ and so the policy is used to experiment regarding pollution. In fact NO2 concentration does increase 12%. Also, there are 12% and 3& more ambulance calls for fever and heart-related problems. So, traffic ongestion has substantial health externalities in China and they’re responsive to policy.
2. Lavaine and Neidall (2013):
* How does breathing sulphur-polluted air during pregnancy affect the
health of baby?
* What would the perfect experiment look like?
* Not feasible: Need to find a quasi- or natural experiment.
* Differences-in-differences…