A committee at London City Hall has cautioned that the proposed expansion of Heathrow Airport could jeopardize advancements in the city’s air quality and expose local residents to “harmful” noise levels, as outlined in a correspondence to the government.

Recently, the government endorsed the airport’s plan for a third runway, which has the potential to boost the annual flight count from 480,000 to 756,000.

In their letter to Transport Secretary Heidi Alexander, the multi-party group – with the exception of Reform UK Assembly Member Keith Prince – expressed that the existing aircraft noise from the various airports in London was already excessively disruptive.

The government emphasized that any airport expansion must align with environmental objectives.

Last month, government officials chose Heathrow’s proposal for a new runway spanning 3.5 km (2.2 miles) along with an underground road tunnel, necessitating the relocation of the M25 motorway.

The Environment Committee conveyed in its letter that the planned expansion might hinder advancements in air quality in London and contradict both local and national climate goals.

The group reminded Ms. Alexander of her previous opposition to the expansion when she held the position of London’s deputy mayor for transport.

They requested that the transport secretary clarify the methods of assessment for the four “tests” related to the expansion—air quality, climate effects, noise levels, and sufficient consultation with London’s residents—prior to progressing with the proposals.

The committee additionally suggested that the government contemplate “caps on overall flight numbers” to mitigate carbon emissions.

In October, Christina Calderato, strategy director at Transport for London, informed the Environment Committee that a third runway would reverse the recent gains made in air quality within the capital.

“We have significant concerns regarding noise pollution, carbon emissions, and air quality; London has worked hard to enhance air quality, and we do not wish to see those improvements used as justification for Heathrow’s expansion,” she remarked.

Committee chair Leonie Cooper, a member of the Labour Assembly, stated: “The proposed Heathrow expansion presents several serious environmental challenges.”

Experts have stressed that such an expansion could negate the recent enhancements in air quality achieved through initiatives like the ULEZ.

Cooper called for the government to “establish rigorous tests to evaluate the effects of the expansion on London’s air quality, noise, and to ensure there are no additional adverse impacts on air quality from airports.”

A representative for the mayor of London communicated to the Local Democracy Reporting Service (LDRS) that Sadiq Khan continues to oppose the third runway at Heathrow Airport, expressing skepticism that a new runway could accommodate hundreds of thousands of additional flights annually without significantly harming the environment.

A Department for Transport spokesperson informed the LDRS that any airport expansion must conform to environmental standards, noting that they are currently reviewing the Airports National Policy Statement to ensure it meets the four criteria concerning climate, air quality, noise, and economic growth.

They added that changes to flight paths would ensure that flights become “quicker, quieter, and cleaner.”