How can local authorities manage traffic-caused air pollution?


Air pollution is a key source of emissions and a growing threat to public health. This article explores what local authorities can do to improve local air quality.

Poor air quality is one of the leading causes of health problems worldwide, harming people, buildings, and the environment. Respiratory and cardiovascular diseases, asthma and allergies, impaired cognition, depression, and poor childhood health have all been linked to air pollution. The impacts were highlighted by the tragic death of nine-year old Ella Kissi-Debrah in London – the first person in the UK to have air pollution listed as a cause of death.


Cycle networks need to be well connected internally and to public transport. They need to be designed to encourage behaviour change with safe crossings and junctions, signposts, lighting, physical barriers when interacting with vehicles and sufficient lockers at destinations, including rail and bus stops. If offices provide shower and changing facilities this can help staff too. Walking buses and cycle trains can be organised to encourage staff and children to use non-motorised transport to get to work and school. Safe alternatives ease pressure on parents and reduces rush hour congestion. Planners should encourage developers to submit plans with equal weighting to non-motorised options and consider connectivity holistically.

One of the advantages of cycling is that it is generally inclusive and does not require expensive equipment so planners should be careful to not inadvertently encourage the “Mamil” image. Networks should be explicitly designed for women, children, and the elderly. This can substantially increase cycling numbers.

Encouraging Active Travel

Alongside creating the right infrastructure there are several ways that local authorities and their partners can encourage the uptake of active travel such as: closing roads to cars on certain days, discouraging the use of private cars, offering inclusive bike hire schemes, clearing cycle paths and walkways of snow and ice, educating children in school and supporting cycle to work schemes.

Urban planning

Urban planning is an important element of improving air quality. Settlements designed for cars are often hostile to active travel and facilitate urban/suburban sprawl. This can lead to disconnected communities which are difficult or dangerous to travel between without a car. New developments constructed without prioritising pedestrian and cycling access can miss opportunities to enable active travel, further contributing to congestion, pollution and emissions which reduces the desirability of the neighbourhood.

One example of this is the 15 or 20-minute neighbourhood concept which seeks to create ‘city-villages’ in which day-to-day needs are met within a mile of a resident’s front door. Advocates argue this makes car journeys less necessary and builds stronger local communities in often lonely urban environments as residents live, work, shop and socialise locally. Balancing the ease, convenience, and freedom of car ownership with social rights to walk and breathe safely is an ongoing policy challenge for municipalities.

Solutions need to appeal to citizens and consider a range of different needs and abilities to become attractive alternatives. Policymakers can over-index vocal lobbying groups and unproven anxieties. Active travel measures are popular and enjoy widespread support. E-bicycles can open cycling up to new users and increase the distances that can be comfortably travelled.

Electric Vehicles (EVs)

Electric cars and vans are the most obvious and straightforward solution to traffic-caused air pollution. Generating no exhaust emissions and allowing people to continue with the mobility options car ownership has accustomed us to. However, non-exhaust emissions (NEE) from tyres, brakes and road wear have been assessed by the UK National Atmospheric Emissions Inventory and the Air Quality Expert Group. This study, prepared for DEFRA, highlights that “60% and 73% (by mass), respectively, of PM2.5 and PM10 emissions from road transport” come from NEE. EVs add to Scope 3 emissions as they require batteries, rare earth metals and the environmental impacts inherent in mining and consumption. They also contribute to a mobility network designed for vehicles over pedestrians and cyclists. Whilst they will play an important role, EVs cannot be seen as a silver bullet.

Vehicle-to-Grid (V2G)

Renewables and electrification will require substantial battery capacity to manage the supply/demand question in the duck curve. This offers local authorities’ opportunities. Policy and consumer trends will increase EV uptake, not only will this dramatically reduce exhaust-based emissions, decarbonising and improving air quality, but will also create significant battery capacity.

KaluzaOvo, and others have been pioneering trials around specialist V2G chargers. Kaluza have produced a case study for Ofgem. Renewables may require costly upgrades to the National Grid; V2G could accelerate renewable deployment by utilising EV batteries instead. The average car is parked 23 hours a day: during surpluses it is charged with electricity sold back to grid during peak periods. Kaluza estimates this could save £3.5bn in grid infrastructure reinforcement, storage, and generation and earn drivers up to £725 a year just for having their vehicle plugged in.

Concerns have been raised over the impact on battery life that could be caused by additional charging/discharging cycles. However, research has indicated the potential to both decrease or extend battery life depending on consumer behaviour. A study led by the University of Warwick has demonstrated that battery life could be extended if optimal charging strategies are followed, which will likely require automation in the charging process as well as consumer education.

Urban Greening

The benefits of green infrastructure are well-known, from mental health and biodiversity to urban heat islands, street values and air quality. Plantings can also be used to create physical barriers between transport modes and redirect polluted air away from residents. Replacing parking spaces with parklets can maximise co-benefits.

Waltham Forest has installed three “CityTree” devices which use moss to purify air. The manufacturer claims one device is equivalent to 275 trees and removes 240 tonnes of carbon dioxide per annum, also implemented in Hong Kong, Paris, Berlin and elsewhere, these trials should be watched with interest to see their real-world impacts.

Direct Measures

Local authorities can also implement measures that directly reduce emissions, such as removing parking bays, reducing speed limits and designating low emission zones. Working with the private sector, councils can support car clubscargo-bikes and cycle-to-work schemes. Lobbying, assistance, and procurement can also shape local ecosystems. Subsidising and increasing the frequency and reliability of public transport is effective. In Southampton, buses were fitted with air filters.


Poor air quality is a major detriment to health, wellbeing, the environment, and cultural heritage. It also impacts economic development and dissuades people from being outside. As cities continue to grow, managing air quality and traffic will be essential. Local authorities need a proactive approach, utilising co-benefits, to improve air quality whilst also achieving health and economic ambitions to achieve vibrant, social and walkable communities.

Oliver Clay is Senior Consultant, Net Zero Cities at WSP in the UK 

This article was originally featured on WSP Insights on 25th April 2023

Feature Image Source: WSPbanner-air-pollution-traffic

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