Heathrow's expansion bid should not be approved without tougher measures to protect communities and passengers, MPs said.
More safeguards on issues such as air quality, noise, regional connectivity and airport charges are needed before the third runway scheme gets the go ahead, according to the Commons' Transport Select Committee.
It called on Parliament to support the project once its concerns have been addressed, accepting there is a case for expanding Heathrow.
The committee wants a more stringent interpretation of air quality laws and for noise estimates to reflect a range of possible flight paths.
A proposed night flight ban of six-and-a-half hours should be extended to seven hours and further evidence is needed that landing charges will not be hiked to pay for expansion, MPs said.
The committee's report also urged the Government to provide more clarity on the funding and timeline of changes to the airport's rail and road links - particularly the M25 - and how it intends to secure 15% of new slots for domestic connections.
In October 2016 the Government announced that a third runway at the west London hub is its preferred option for increasing airport capacity in south-east England.
Outline planning consent will be given by Parliament if it approves a National Policy Statement (NPS) setting out objectives and requirements for the scheme.
The final NPS is due to be published by the Government for a vote in the Commons by the end of July.
The Transport Select Committee warned that the project is at risk of a successful legal challenge unless the draft NPS released in February 2017 is amended in line with its recommendations.
Committee chairwoman Lilian Greenwood said: "Thousands of people across London could be exposed to worse levels of noise, air quality and traffic congestion.
"There must be sufficient measures to protect or compensate them."
Heathrow is the busiest airport in Europe with 78 million passengers in 2017.
A third runway would allow hundreds of thousands more flights a year.
If the scheme is approved by Parliament, Heathrow will submit a planning application after consulting local communities on detailed proposals.
An airport spokesman said: "This report couldn't be clearer - Heathrow is the right answer for the UK and Parliament should green light the policy for Heathrow expansion and allow the project to move into the planning phase.
"We are also clear that we will deliver an expanded Heathrow that is sustainable, affordable and financeable and maintains Britain's position as a global trading powerhouse."
A Department for Transport spokeswoman said the report was "very clear" that a third runway at Heathrow is the best option for delivering more airport capacity.
She added: "Expansion will only proceed if it meets strict environmental obligations and offers a world-class package of compensation and mitigations for local communities."
The Government will consider the committee's recommendations and remains "on track" to publish the final NPS in the first half of the year, the spokeswoman added.
The airport hopes to begin construction in early 2021, with the runway completed by the end of 2025.